Gene therapy is very attractive because its ability to cure conventionally incurable diseases on the genetic level. For gene therapy, a gene responsible for curing a disease must be carried by a carrier, which are typically classified into viral and non-viral vectors.
In spite of low delivery efficiency, non-viral vectors have been extensively studied because of the safety thereof.
Of the non-viral vectors, polyethyleneimine (PEI) is recognized to have highly efficient gene delivery and serve as an effective gene carrier in vitro and in vivo (O. Boussif, F. Lezoualc'h, M. A. Zanta, M. D. Mergny, D. Scherman, B. Demeneix, J. P. Behr, A versatile vector for gene and oligonucleotide transfer into cells in culture and in vivo: polyethylenimine. Proc. Natl. Acad. Sci. USA 92 (1995) 7297-7301; and W. T. Godbey, K. K. Wu, A. G. Mikos, Poly(ethylenimine) and its role in gene delivery, J. controlled Release 60 (1999) 149-160).
Korean Pat. Unexamined Publication No. 2006-25711 discloses a gene carrier composed mainly of a copolymer of polyethyleneimine and polyether as a substitute for PEI 25K which although high in gene transfer efficiency is of limited use in practical application due to the high cytotoxicity thereof.
However, there is still a need for gene carriers which are more efficient and of lower cytotoxicity.